The invention relates to an electrical connector, comprising a housing of electrically insulating material provided with a plurality of contact elements of electrically conducting material, each having a contact side for making contact to a further connector and a connecting side in the form of connecting pins extending outside the housing and having a connecting end for mounting on a printed circuit board, and having a body of plastically deformable synthetic material provided with parts which extend between the respective connecting pins.
Electrical connectors provided with a body surrounding the connecting pins as described above are known per se in practice. Such a body is referred to by the term "wafer".
In practice, two types of bodies surrounding the connecting pins of a connector can be distinguished, i.e. bodies which essentially surround the connecting ends of the connecting pins and bodies which extend over the entire connecting side of the connector between the connecting pins.
Bodies of the type first mentioned, such as disclosed by U.S. Pat. No. 4,686,607 essentially have the object of preventing deviations in the predetermined mutual pitch spacing of the connecting ends of the connecting pins, for example caused by bending during transportation or assembly of the connector, in order to facilitate the electrical connection of the connecting ends in correspondingly spaced openings and/or connecting pads on a printed circuit board, which is advantageous, in particular, in connectors having a large number of contact elements and in machine assembly using, for example, an assembly robot.
The bodies of the second type, such as disclosed by U.S. Pat. No. 4,986,772 provide, in addition to maintaining the desired positioning of the connecting ends, also an electrical and mechanical protection for the connecting pins, so that, for example, mutual short circuiting between connecting pins is effectively prevented. Undesirable touching of one or more connecting pins can also be effectively prevented in this way. It will be clear that the bodies of the second type have a larger size than the bodies of the first type described above. The bodies of the second type can also be used to introduce the contact elements into the housing of the connector.
In order to guarantee an optimum positioning of the connecting ends of the connecting pins, it is advantageous to keep the bodies during transportation and assembly of the connectors as close as possible to the connecting ends of the connecting pins. During mounting on a printed circuit board, the body is then pushed upwards along the connecting ends, so that it rests on the board. The connecting ends are then free to be electrically connected to the respective terminal pads of the printed circuit board.
The holding of the body between the connecting ends is achieved in practice by giving one or more of the through openings of the body dimensions which are such that the respective connecting ends fit therein with a clamping action. The clamping fixing obtained in this way is generally sufficient both to hold the body in place and to make it slidable during the assembly of the connector.
The disadvantage of this method of fixing is the narrow tolerance requirements between the through openings of the body and the connecting pins of the connector. When the body is being fitted, the longer pins must be adequately supported to prevent bending or deformation of said pins during assembly of the body, that is to say the fitting of the connecting ends in the through holes with a clamping action. For these reasons, only one or more of the through openings is or are designed as a clamping fit for receiving the shortest connecting pins, in general those situated closest to the connecting side of the connector housing. It has been found that this can provide an adequate holding force for the above-described bodies of the first type.
For the more extensive protective bodies of the second type mentioned, which, to surround an identical number of connecting pins, are consequently proportionally more heavy in weight than the bodies of the first type, the clamping-fit design of one or more of the through openings of the body for receiving the shortest connecting pins of a connector is in general not adequate. There is the danger that the body, as a consequence of its greater weight, slides off the connecting pins. The clamping-fit design of a plurality of through openings of the body again entails the above-described disadvantage of narrower tolerances and the risk of connecting pins bending while the body is being fitted and during assembly on the printed circuit board.